Microchimerism and HLA-compatible relationships of pregnancy in scleroderma

Loss of tolerance to a maternal kidney transplant is selective for HLA class II: evidence from trans-vivo DTH and alloantibody analysis

We studied late graft rejection in a patient who had received a kidney transplant 9-10 years earlier from his mother and who had been off all immunosuppressive drugs for 7 years at the time of graft rejection onset. The mother differed for one HLA-A (A3) and one HLA-B (B62) antigen but had only a subtype mismatch at the HLA-DR beta 1 locus (donor: DR beta 1*1104; recipient: DR beta 1*1102). A gradual rise in serum creatinine from 1.8 to 2.0 mg/dl at year 9 prompted a biopsy, which was negative for rejection (focal infiltrates but no tubulitis). Ten months later the patient's creatinine had risen to > 3.4 mg/dl, and a second biopsy revealed extensive tubulitis, cellular rejection, and glomerular sclerosis. Sonicates of donor leukocytes triggered no delayed-type hypersensitivity (DTH) response above background (PBMC only) in the patient's peripheral blood leukocytes obtained prior to year 9. A gradual recovery of antidonor DTH response between year 9 and 10 closely paralleled the change from tolerant to rejection status. Antidonor antibody was also undetectable in serum prior to year 9, but a donor-reactive antibody did develop at year 10.2 shortly after the peak of DTH response. The serum level of soluble donor HLA class I B62 antigen rose > 10-fold over prerejection level at the time of the biopsy-proven rejection, suggesting a possible trigger for both the cellular and humoral immune response. Nonetheless, we found no evidence for the development of humoral or cellular immunity to maternal HLA class I. Instead, DTH analysis of memory T cells of the patient obtained after rejection showed that a single maternal HLA DR beta 1*1104 allopeptide, differing by two amino acids in sequence from the peptide of the recipient (DR beta 1*1102), stimulated a strong memory DTH response. Similarly, we found an anti-HLA class II donor-specific antibody in serum that appeared to be crossreactive with DR beta 1*1104 and DR beta 1*1101 but not with the recipient DR beta 1*1102 antigen. The data support the idea of a profound unresponsive state at both the cellular (DTH) and humoral level toward maternal HLA class I antigens that was not reversed even during late cellular rejection, despite the release of high levels of soluble HLA class I. Furthermore, the data suggest that DTH recovery was a close correlate of the onset of rejection and this "indirect" alloresponse, like the anti-donor alloantibody response that followed, was directed not to noninherited maternal HLA-A,B antigens but to the maternal HLA DR beta 1*1104 subtype.

Increased numbers of microchimeric cells of fetal origin are associated with dermal fibrosis in mice following injection of vinyl chloride

OBJECTIVE

To develop a murine model for use in examining the role of microchimeric cells and certain chemical exposures in the pathogenesis of systemic sclerosis (SSc).

METHODS

Female BALB/cJ retired breeder mice were bled before and after vinyl chloride injection. The DNA from their white blood cells was obtained, and the number of microchimeric cell equivalents was determined by quantitative polymerase chain reaction using DNA primers specific for the H-2Kb gene, a sequence not found in BALB/cJ mice. Skin was obtained at autopsy, embedded in paraffin, sectioned, and stained with Masson's trichrome. Hydroxyproline analyses were performed on 4-mm skin biopsy samples.

RESULTS

Microchimeric cells were identified and quantitated before and after 20 daily intraperitoneal injections of vinyl chloride. The number of microchimeric cells in the peripheral blood increased an average of 48-fold after treatment with vinyl chloride. Histologic examination of the skin of these same mice (which had an increased number of microchimeric cells) showed inflammation, with abundant fibroblasts and a heavy mononuclear infiltration in the dermis. The collagen fibers appeared densely packed and disorganized. Histologic examination of the skin of untreated retired breeder mice and treated virgin mice appeared normal. Quantitative assays to determine the collagen content of skin biopsy samples obtained from treated microchimeric mice compared with nontreated microchimeric or with treated nonmicrochimeric mice showed a 2-3-fold increase in collagen content in the treated microchimeric mice. Extraordinary splenomegaly was present in the vinyl chloride-treated microchimeric mice, accompanied by cellular infiltration and fibrosis.

CONCLUSION

The results suggest that vinyl chloride injections into BALB/cJ retired breeder mice lead to activation of microchimeric cells, which causes the cells to divide and multiply. The correlation between the 48-fold increase in microchimeric cells and the appearance of dermal inflammation and fibrosis similar to that of graft-versus-host disease suggests that activated microchimeric cells may be a necessary factor in the pathogenesis of autoimmune diseases such as SSc.

Detection of male DNA in the liver of female patients with primary biliary cirrhosis

BACKGROUND/AIMS

Primary biliary cirrhosis is a chronic cholestatic liver disease characterized by progressive inflammatory destruction of bile ducts, with eventual hepatic fibrosis and cirrhosis. Since primary biliary cirrhosis affects predominantly middle-aged women and has pathological similarities to hepatic graft-versus-host-disease, we investigated whether fetal cell microchimerism might be involved in the development of this disease.

METHODS

The presence of Y-chromosome-specific sequences was analyzed by polymerase chain reaction using peripheral blood mononuclear cells from women with primary biliary cirrhosis (n=18) and healthy (control) women (n=18), and by in situ hybridization of liver biopsy sections from women with primary biliary cirrhosis (n=19) and women with chronic hepatitis C or alcoholic liver disease (n=20).

RESULTS

Male cells were detected in liver biopsy specimens of 8 of 19 patients (42%) with primary biliary cirrhosis. Y-chromosome-containing cells were not seen in any of the liver biopsy specimens from women with chronic hepatitis C or alcoholic liver disease. Male cells were detected in peripheral blood mononuclear cells from one healthy control at a level of 1 male cell per 10(6) female cells, but were not detected in peripheral blood mononuclear cells of women with primary biliary cirrhosis.

CONCLUSIONS

The presence of male cells in the liver of women with primary biliary cirrhosis raises the possibility that fetal cell microchimerism may be involved in the pathogenesis of this chronic liver disease.

Fetal microchimerism in primary biliary cirrhosis

BACKGROUND/AIMS

Recent studies have suggested a role of fetal microchimerism in the pathogenesis of scleroderma. The present study investigated the potential role of fetal microchimerism in primary biliary cirrhosis (PBC), a closely related disease.

METHODS

A quantitative nested polymerase chain reaction was used to detect Y-chromosome sequences in the peripheral blood or the liver of PBC women and controls having male children and no transfusion or miscarriage history.

RESULTS

Male microchimerism was found in the peripheral blood from 45% (9 of 20) of PBC women and 25% (5 of 20) of healthy controls matched for the number of male children and age of the youngest son (p=0.28), and in the liver-biopsy specimens from 33% (5 of 15) of PBC women and 32% (8 of 25) of controls. The level of chimerism did not differ between patients and controls either in blood or in liver. Microchimerism was not related to the severity of the disease but was more frequent in PBC patients with anticentromere antibodies (p=0.049).

CONCLUSIONS

Fetal microchimerism does not seem to play a major role in most cases of PBC. However, the association with anticentromere antibodies suggests a possible role in the subgroup of patients with CREST syndrome or scleroderma.

Fetal cells in the mother: from genetic diagnosis to diseases associated with fetal cell microchimerism

Fetal cells circulate in the blood of pregnant women. When the gestation is normal, fetal cells are low in number. Complications of pregnancy, such as pre-eclampsia, or fetal cytogenetic abnormalities, such as Down's syndrome, increase fetomaternal transfusion. The isolation of fetal cells from maternal blood is currently under active investigation as a non-invasive method for prenatal diagnosis. The fetal cells that are most commonly used for non-invasive genetic diagnosis, the nucleated erythrocyte and the trophoblast, are highly differentiated and do not persist post-partum. In the context of studying fetal cells in maternal blood it was discovered that fetal progenitor cells originating from a prior pregnancy could also be detected. This led to the appreciation that unlike fetal DNA in plasma, which is cleared almost immediately following delivery, fetal cells persist for decades post-partum. Following pregnancy, labor, and delivery, a woman becomes a chimera. Transfused fetal stem and progenitor cells appear to be capable of further differentiation and migration to maternal organs. A further research agenda is needed to explore the newly appreciated phenomenon of bi-directional fetomaternal cell trafficking. Any consideration of the fetus as a patient must also consider the fetus as a potential source of therapeutic stem cells for the mother.

Quantitative Analysis of the Bidirectional Fetomaternal Transfer of Nucleated Cells and Plasma DNA

Background: Recently, much interest has been generated on the fetomaternal transfer of nucleated cells and plasma DNA. However, there has been no systematic quantitative comparison of these two directions and two modalities of trafficking within the same study population.

Methods: The fetus-to-mother transfer of nucleated cells and plasma DNA in pregnant women carrying male babies was studied using a real-time quantitative PCR assay for the SRY gene. For mother-to-fetus transfer, real-time quantitative PCR assays for the insertion/deletion polymorphisms involving the glutathione S-transferase M1 and angiotensin-converting enzyme genes were used.

Results: Of the 50 informative mother-baby pairs, maternal DNA was detected in the cellular fraction of umbilical cord blood in 24% of cases (12 of 50), at a median fractional concentration of 2.6 × 10−4 (interquartile range, 1.7 × 10−4 to 3.6 × 10−4). In the plasma fraction of cord blood, maternal DNA was detected in 30% (15 of 50) of cases at a median fractional concentration of 3 × 10−3 (interquartile range, 1 × 10−3 to 1.6 × 10−2). For the other direction of trafficking, fetus-to-mother transfer of nucleated cells was detected in 26% of cases (13 of 50) at a median fractional concentration of 3.2 × 10−4 (interquartile range, 0.6 × 10−4 to 7.6 × 10−4). In the plasma fraction, fetal DNA was detected in 100% of maternal plasma (50 of 50) at a median fractional concentration of 3 × 10−2 (interquartile range, 1.4 × 10−2 to 5.3 × 10−2).

Conclusions: This study indicated that significantly more fetal DNA is present in the plasma of pregnant women compared with DNA from the cellular fraction of maternal blood. In addition, maternal DNA was demonstrated in both the cellular and plasma fractions of cord blood after delivery. This study has therefore determined the fundamental quantitative values for the bidirectional fetomaternal cellular and plasma DNA traffic.

HLA-DQA1*0501 is associated with diffuse systemic sclerosis in Caucasian men

OBJECTIVE

Systemic sclerosis (SSc) is uncommon in men, and relatively little is known about factors contributing to its pathogenesis in this population. In the current study, we investigated HLA class II alleles in men with SSc. We also investigated the hypothesis that HLA compatibility of the mother could be a risk factor for SSc in men.

METHODS

Sequence-specific oligonucleotide probe typing was used to determine DQA1, DQB1, and DRB1 alleles of SSc patients (50 men and 36 parous women), healthy controls (59 men and 80 parous women), 26 mothers of men with SSc, and 44 mothers of healthy men. All study subjects were Caucasian, and allele frequencies were compared with those of Caucasian controls from the Eleventh International Histocompatibility Workshop as well as those of local controls.

RESULTS

The DQA1*0501 allele was significantly increased among men with SSc compared with healthy men (odds ratio [OR] 2.3, P = 0.006, Pcorr = 0.04). DQA1*0501 was associated with diffuse SSc in men (OR 3.0, P = 0.004, Pcorr = 0.03), but not with limited SSc in men. Maternal HLA compatibility was not a risk factor for SSc in men.

CONCLUSION

Previous studies have shown associations of DRB1 alleles with SSc, but have rarely determined DQA1 allele frequencies. Our findings indicate that a specific DQA1 allele is associated with SSc, and that DRB1 associations may be due to linkage disequilibrium with DQA1. Moreover, by analyzing genetic susceptibility according to sex, we found that the contribution of HLA genes to the risk of SSc was substantially greater in men than in parous women.

Fetal cells from maternal blood: purpose, biological questions, technical challenges

The maternal peripheral blood circulation can serve as a source of fetal cells for the prenatal diagnosis of genetic abnormalities, eliminating the need for fetal cell sampling by invasive techniques. However, the extreme scarcity of these cells leads to a variety of biological questions and technical hurdles on the way to a clinical test. On the biological side, we need to know the numbers of fetal cells, their distinguishing properties, and the variables that affect these properties. On the technical side, we need to identify fetal cells and maximize both yield and purity of the isolation procedure. Here we review the questions and challenges as they present themselves in our specific approach to the fetal cell isolation project. We also briefly discuss the question of whether these cells could help to diagnose fetal infections.

Microchimerism in bone marrow–derived CD34+ cells of patients after liver transplantation

Lymphoid and dendritic cells of donor origin can be detected in the recipient several years after a solid organ transplantation. This phenomenon is termed microchimerism and could play a role in the induction of tolerance. The fate of other hematopoietic cells transferred by liver transplantation, in particular of stem and progenitor cells, is unknown. For this reason, we studied peripheral blood and bone marrow samples of 12 patients who had received a liver transplant from an HLA-DR mismatched donor. Eight patients were long-term survivors between 2.8 and 10.1 years after allografting. CD34+ cells from bone marrow were highly enriched with the use of a 2-step method, and a nested polymerase chain reaction was applied to detect donor cells on the basis of allelic differences of the HLA-DRB1 gene. Rigorous controls with DRB1 specificities equal to the donor and host were included. In 5 of 8 long-term liver recipients, donor-specific CD34+ cells could be detected in bone marrow. Microchimerism in the CD34+ cell fraction did not correlate to the chimeric status in peripheral blood. In conclusion, our results demonstrate a frequent microchimerism among bone marrow–derived CD34+ cells after liver transplantation. The functional role of this phenomenon still needs to be defined.

Microchimerism in bone marrow–derived CD34+ cells of patients after liver transplantation

Lymphoid and dendritic cells of donor origin can be detected in the recipient several years after a solid organ transplantation. This phenomenon is termed microchimerism and could play a role in the induction of tolerance. The fate of other hematopoietic cells transferred by liver transplantation, in particular of stem and progenitor cells, is unknown. For this reason, we studied peripheral blood and bone marrow samples of 12 patients who had received a liver transplant from an HLA-DR mismatched donor. Eight patients were long-term survivors between 2.8 and 10.1 years after allografting. CD34+ cells from bone marrow were highly enriched with the use of a 2-step method, and a nested polymerase chain reaction was applied to detect donor cells on the basis of allelic differences of the HLA-DRB1 gene. Rigorous controls with DRB1 specificities equal to the donor and host were included. In 5 of 8 long-term liver recipients, donor-specific CD34+ cells could be detected in bone marrow. Microchimerism in the CD34+ cell fraction did not correlate to the chimeric status in peripheral blood. In conclusion, our results demonstrate a frequent microchimerism among bone marrow–derived CD34+ cells after liver transplantation. The functional role of this phenomenon still needs to be defined.

Cutting edge: persistent fetal microchimerism in T lymphocytes is associated with HLA-DQA1*0501: implications in autoimmunity

The host's MHC genotype plays a critical role in susceptibility to autoimmune diseases. We previously proposed that persistent fetal microchimerism from pregnancy contributes to the pathogenesis of autoimmune diseases such as scleroderma. In the current study, we investigated whether the specific host MHC genotype is associated with persistent microchimerism among T lymphocytes in women with scleroderma and in healthy women. Fetal microchimerism among T lymphocytes was strongly associated with HLA DQA1*0501 of the mother (odds ratio (OR) = 13.5, p = 0.007, p corrected (pc) = 0.06) and even more strongly with DQA1*0501 of the son (OR = infinity; p = 0. 00002, pc = 0.0002). This is the first description of an association between persistent fetal microchimerism in maternal T lymphocytes and specific HLA class II alleles. Although the association was observed in both healthy women and in women with scleroderma, the finding suggests an additional route by which HLA genes might contribute to susceptibility to autoimmune disease.

Survival of donor cells 25 years after intrauterine transfusion

Persistence of donor leukocytes in the circulation of recipients of intrauterine transfusion (IUT) has been observed up to 5 years after birth. The aim of this study was to determine whether transfusions with nonirradiated, nonleukocyte-depleted donor blood during the fetal period resulted in long-term immunomodulation of the recipient. Twenty-four surviving IUT recipients between 1966 and 1976 were tested for autoimmune disease and autoantibodies at follow-up. Ten had sex-mismatched donors and were therefore informative for chimerism studies using fluorescence in situ hybridization (FISH). Seven female recipients could be tested for chimerism using a Y- chromosome–specific polymerase chain reaction (PCR) because they received at least 1 IUT from a male donor. Nine recipients could be studied for cytotoxic T-lymphocyte precursor (CTLp) and helper T-lymphocyte precursor (HTLp) frequencies because the original donors were available for testing. All surviving IUT recipients were in good health at the time of the examination, and routine laboratory testing revealed no abnormalities. None of the IUT recipients were chimeric as determined by FISH analysis, but Y-chromosome–specific sequences were detected by PCR in 6 of the 7 women. However, the CTLp and HTLp frequencies of the IUT recipients against the donors were comparable to those of the controls. The current study provides evidence that IUT can result in the persistence of donor cells in the recipient for a period longer than 20 years but that it is not associated with immunotolerance or with signs of chronic antigenic stimulation.

Survival of donor cells 25 years after intrauterine transfusion

Persistence of donor leukocytes in the circulation of recipients of intrauterine transfusion (IUT) has been observed up to 5 years after birth. The aim of this study was to determine whether transfusions with nonirradiated, nonleukocyte-depleted donor blood during the fetal period resulted in long-term immunomodulation of the recipient. Twenty-four surviving IUT recipients between 1966 and 1976 were tested for autoimmune disease and autoantibodies at follow-up. Ten had sex-mismatched donors and were therefore informative for chimerism studies using fluorescence in situ hybridization (FISH). Seven female recipients could be tested for chimerism using a Y- chromosome–specific polymerase chain reaction (PCR) because they received at least 1 IUT from a male donor. Nine recipients could be studied for cytotoxic T-lymphocyte precursor (CTLp) and helper T-lymphocyte precursor (HTLp) frequencies because the original donors were available for testing. All surviving IUT recipients were in good health at the time of the examination, and routine laboratory testing revealed no abnormalities. None of the IUT recipients were chimeric as determined by FISH analysis, but Y-chromosome–specific sequences were detected by PCR in 6 of the 7 women. However, the CTLp and HTLp frequencies of the IUT recipients against the donors were comparable to those of the controls. The current study provides evidence that IUT can result in the persistence of donor cells in the recipient for a period longer than 20 years but that it is not associated with immunotolerance or with signs of chronic antigenic stimulation.

Fetal DNA in maternal plasma

Recently, cell-free fetal DNA has been found in maternal plasma and serum. This discovery opens up a new field of investigation and provides an easily accessible source of fetal genetic material for prenatal diagnosis. Prenatal diagnostic applications of fetal DNA in maternal plasma include the investigation of sex-linked disorders and fetal rhesus D status determination. Cell-free fetal DNA has been found to be present in much higher fractional concentrations than fetal nucleated cells in maternal blood. The concentration of fetal DNA increases throughout pregnancy, with a sharp rise towards the end of gestation. Abnormally high levels of cell-free DNA have been found in pregnancies complicated by preeclampsia and preterm labor, an observation that has potential diagnostic and pathophysiologic implications. Much remains to be learned regarding the mechanisms of production and clearance of maternal plasma fetal DNA. It is hoped that the eagerly awaited answers to these and other questions may ultimately enhance our understanding of the fetomaternal relationship.

Fetomaternal cell trafficking: a new cause of disease?

Isolation of fetal cells from maternal blood is under active investigation as a noninvasive method of prenatal diagnosis. In the context of studying cell surface antigens expressed on fetal cells we discovered that fetal cells from a prior pregnancy also could be detected. This led to the appreciation of the persistence of fetal cells in maternal blood for as long as 27 years postpartum, and the realization that following pregnancy, a woman becomes a chimera. Quantitative polymerase chain reaction analyses have shown that a term pregnancy is not required for the subsequent development of fetal cell microchimerism. As many as 500,000 fetal nucleated cells are transfused following an elective first trimester termination of pregnancy. The relationship between fetal cell microchimerism and maternal disease is currently being explored. During pregnancy, fetal cells in the maternal skin are related to polymorphic eruptions of pregnancy and increased fetomaternal trafficking is detectable in cases of preeclampsia. After delivery, more male DNA of presumed fetal origin is present in the blood and skin of women with scleroderma as compared with healthy controls. Scleroderma is of particular interest because it shows a strong female predilection and it is an autoimmune disease with clinical similarities to graft-versus-host disease. Fetomaternal cell trafficking provides a potential explanation for the increased prevalence of autoimmune disorders in adult women following their childbearing years.

Immunological tolerance in an HLA non-identical chimeric twin

Blood group chimeric twins offer a unique opportunity to study immunological tolerance in humans. Although this condition is not as rare as previously considered, detailed immunological studies of blood group chimeras are lacking. We describe here a case of secondary chimerism in a dizygotic twin of opposite gender. The karyotypes of the cultured fibroblast confirmed the sex of each twin, all cells in the boy were 46, XY and all cells in the girl were 46, XX. Molecular HLA typing on fibroblasts revealed HLA-DR, DQ and DP disparities between the two siblings. Mixed lymphocyte culture (MLC) revealed a mutual absence of alloreactivity.

Fetal microchimerisms in the mother: immunologic implications

The previously held concept that the fetus is completely separated from the mother, especially by trophoblasts that line the outer layer of the placenta, has recently been questioned. It has recently been shown that fetal cells are detectable not only in the peripheral blood, but also in maternal skin and liver. Although the migration of fetal cells into the maternal circulation has been given a great deal of attention because of its implication in the prenatal diagnosis of genetic diseases, the potential role of such placental transfer of fetal cells in the pathogenesis of autoimmune diseases has only recently been considered. In patients with scleroderma, fetal cell-derived DNA was detected more frequently in the peripheral blood of patients than controls. This finding of a limited number of fetal cells in maternal tissues leading to microchimerism has been proposed to have a role in the induction of scleroderma. Although evidence for microchimerism has also been confirmed in a high frequency of liver tissues from patients with primary biliary cirrhosis (PBC), a similar high frequency was noted in control patients, which suggests that microchimerism by itself is unlikely to fully account for the pathogenesis of PBC. The finding of such a high frequency of fetal microchimerism in the liver suggests that this is a very common event, raising the possibility that the migration of fetal cells may be important in the induction and subsequent maintenance of tolerance against the fetus during pregnancy. In addition, it is clearly possible that such microchimerism could contribute to the pathogenesis of select autoimmune diseases.

Bone Marrow Transplantation for Non-Malignant Disease

This article reviews the experience in hematopoietic stem cell transplantation (HSCT) for non-malignant disease. HSCT has long been applied as treatment of life-threatening congenital immunodeficiency and metabolic diseases. In Section I, Dr. Parkman reviews that experience for severe combined immunodeficiency, Wiscott-Aldrich syndrome, hyper IGM syndrome, Chédiak-Higashi disease and hereditary lymphohistiocytosis. The value of HSCT in genetic metabolic diseases such as osteopetrosis, osteogenesis imperfecta and the storage diseases are reviewed. In Section II, Dr. Walters reviews the experience over the last decade with allogeneic stem cell transplantation in patients with thalassemia major and sickle cell disease. In Section III, Dr. Sullivan reviews the more recent investigations using stem cell transplantation in patients with advanced autoimmune diseases such as systemic sclerosis, systemic lupus erythematosus, multiple sclerosis and juvenile rheumatoid arthritis. The pathogenesis and outcome with conventional care of these patients, the selection criteria and current results for HSCT, and the future directions in clinical research and patient care using this modality are addressed.

Bone Marrow Transplantation for Non-Malignant Disease

This article reviews the experience in hematopoietic stem cell transplantation (HSCT) for non-malignant disease. HSCT has long been applied as treatment of life-threatening congenital immunodeficiency and metabolic diseases. In Section I, Dr. Parkman reviews that experience for severe combined immunodeficiency, Wiscott-Aldrich syndrome, hyper IGM syndrome, Chédiak-Higashi disease and hereditary lymphohistiocytosis. The value of HSCT in genetic metabolic diseases such as osteopetrosis, osteogenesis imperfecta and the storage diseases are reviewed. In Section II, Dr. Walters reviews the experience over the last decade with allogeneic stem cell transplantation in patients with thalassemia major and sickle cell disease. In Section III, Dr. Sullivan reviews the more recent investigations using stem cell transplantation in patients with advanced autoimmune diseases such as systemic sclerosis, systemic lupus erythematosus, multiple sclerosis and juvenile rheumatoid arthritis. The pathogenesis and outcome with conventional care of these patients, the selection criteria and current results for HSCT, and the future directions in clinical research and patient care using this modality are addressed.

Fetal hematopoietic stem cell transplantation

In utero hematopoietic stem cell transplantation (IUHSCTx) is a promising approach for the treatment of a potentially large number of fetuses affected by congenital hematologic disorders. With technical and molecular advances in prenatal diagnosis, the majority of these diseases can now be diagnosed early in gestation, allowing consideration of prenatal treatment. In addition, technical advances in fetal imaging and intervention make it possible to perform the transplants with relatively minimal risk. It, therefore, stands to reason that there is increasing interest in performing in utero hematopoietic stem cell transplantation at many fetal treatment centers. Although the approach remains experimentally promising, expansion of clinical application will depend on improved understanding of the biological barriers to engraftment in the fetus as well as the development of effective clinical strategies based on the hematopoietic biology of individual disorders. This article presents the current status of this emerging therapeutic approach.

[Influence of age on the clinical and biological characteristics of systemic scleroderma]

PURPOSE

The present study was aimed at assessing the influence of age on clinical and biological features of systemic sclerosis.

METHODS

This retrospective study included 151 consecutive patients with systemic sclerosis. The median age at diagnosis was 50.0 years (range: 10-84 years). Patients were divided into two groups according to their age (lower than 50.0 years of age: 73 patients, equal to or above 50 years of age: 78 patients). The following features were compared between the two groups: gender, disease duration, extent of skin sclerosis, Crest syndrome, lung fibrosis, secondary Sjögren's syndrome, antinuclear, anticentromere, and anti-Scl70 antibodies.

RESULTS

The disease duration was significantly higher in patients over 50 years of age (7.1 +/- 6.8 years vs 5.5 +/- 5.0 years, P < 0.05). Crest syndrome, secondary Sjögren's syndrome and anticentromere antibodies were significantly more common in patients over 50 years of age (17/73 vs 30/78, P < 10(-2); 9/73 vs 20/78, P < 10(-2), and 19/73 vs 31/78, P < 0.05; respectively). Anti-Scl70 antibodies were significantly more common in patients under 50 years of age (17/73 vs 10/78, P < 10(-2)). No significant difference was found in regard to the other features.

CONCLUSION

The clinical and biological patterns of systemic sclerosis are different according to the age at disease onset. Crest syndrome including anticentromere antibodies and Sjögren's syndrome is more common in elderly patients, while anti- Scl-70 antibodies are more common in younger patients. This suggests the involvement of various mechanisms in the pathogenesis of systemic sclerosis, and that these mechanisms may depend on the age.

Anti-TGF-β Treatment Prevents Skin and Lung Fibrosis in Murine Sclerodermatous Graft-Versus-Host Disease: A Model for Human Scleroderma

Scleroderma, a debilitating acquired connective tissue disease, is characterized by fibrosis, particularly of the skin and lungs. Monocyte-produced TGF-β1, a potent stimulus for collagen synthesis, is thought to drive the fibrosis. Here, we thoroughly characterize a murine sclerodermatous graft-vs-host disease (Scl GVHD) model for scleroderma that reproduces important features of scleroderma including skin thickening, lung fibrosis, and up-regulation of cutaneous collagen mRNA, which is preceded by monocyte infiltration and the up-regulation of cutaneous TGF-β1 mRNA. Most importantly, we can prevent fibrosis in both the skin and lungs of mice with Scl GVHD by inhibiting TGF-β with neutralizing Abs. The murine Scl GVHD model provides the unique opportunity to study basic immunologic mechanisms that drive fibrosing diseases and GVHD itself and will be useful for testing new therapies for these diseases.

A case of dermatomyositis that developed after delivery: the involvement of pregnancy in the induction of dermatomyositis

A relationship between dermatomyositis (DM) and pregnancy has rarely been documented, and most cases have been reported from the viewpoint of the management of high-risk pregnancy. We report a patient with DM which developed after the delivery of a healthy infant. This case, with support from a literature review, suggests that pregnancy could be a trigger for the development of DM. Furthermore, it is suggested that there are at least two types of pregnancy related DM: in one type, the disease activity is provoked during pregnancy and tends to improve after delivery, while the other type (including the present case) has onset in the postpartum period.

First trimester prenatal diagnosis: fetal cells in the maternal circulation

The recovery of fetal cells from the maternal circulation represents a promising approach to noninvasive prenatal diagnosis. Advances in techniques of sensitive molecular genetic analysis have enabled the conclusive demonstration of the presence of fetal cells in maternal blood. In most pregnancies, there are few fetal cells detectable. In some abnormal pregnancies, there appears to be increased fetomaternal transfusion, which facilitates recognition of aneuploid fetal cells. This review article describes general strategies of fetal cell isolation, current technical challenges, and clinical applications that are envisioned for the future. The increased appreciation of fetal cell microchimerism, and its association with complications of pregnancy and the postpartum development of autoimmune disease, is also discussed.

Microchimerism and scleroderma

It is now known that cells traffic between fetus and mother during normal human pregnancy. Moreover, fetal cells have been found to persist in the maternal peripheral blood for decades after childbirth. Chronic graft-versus-host disease, a known condition of chimerism that occurs after allogeneic hematopoietic stem cell transplantation has clinical similarities to some autoimmune diseases, including scleroderma (SSc). SSc has a predilection for women and an increased incidence in women following childbearing years. These observations when considered together with the longterm persistence of fetal cells led to the hypothesis that microchimerism is involved in autoimmune diseases such as SSc. Initial studies of women with SSc lend support to the hypothesis. Microchimerism, however, is also very common in healthy normals, and available data is not sufficient to be conclusive with respect to disease pathogenesis. Microchimerism can also occur due to engraftment from a blood transfusion, from a twin, or from the mother, sources that are applicable to men and women who have never been pregnant. The mechanism(s) by which microchimerism might contribute to SSc are not known, although some insight may be gained from studies of chimerism in transplantation biology. If microchimerism does contribute to the pathogenesis of autoimmune disorders such as SSc, it is likely that new therapeutic strategies could be developed.

Fetal microchimerism alone does not contribute to the induction of primary biliary cirrhosis

Microchimerism has been implicated in the etiology of autoimmune diseases. It has also been implicated in the induction/maintenance of fetal tolerance. We used polymerase chain reaction (PCR) analysis to determine whether microchimerism occurred in patients who subsequently developed primary biliary cirrhosis (PBC), and thus may be involved in its etiology. We performed PCR amplification of sequences unique to both the X and Y chromosomes from the livers of 37 women with PBC and 39 female controls using WAVE technology; a very sensitive technology based on an ion-pair reverse-phase high-performance liquid chromatography system. All patients were known to have had at least 1 son and it was confirmed that PBC was diagnosed after the birth of the son. Data were analyzed for both detection of the Y chromosome gene and the ratio of the yield of the Y chromosome PCR products to the X chromosome. The prevalence of Y chromosome detection in PBC was 26 of 37 (70%) compared with 28 of 39 (72%) in controls, and the ratio of Y chromosome to X chromosome was similar between the PBC and control groups, 0.402 +/- 0.143 vs. 0.271 +/- 0.055, respectively. Our results, using our more sensitive technology, showed that microchimerism is a very common event in human liver and supported the thesis that this may contribute to the induction/maintenance of fetal tolerance. However, although we cannot exclude the possibility that select fetal major histocompatibility complex (MHC) haplotypes might contribute to disease susceptibility, our data suggest that microchimerism by itself does not play a significant role in the development of PBC.

Microchimerism: implications for autoimmune disease

Recent studies indicate cells traffic between the fetus and mother during normal human pregnancy and that fetal cells persist in maternal peripheral blood for decades after childbirth. The long-term persistence of fetal cells, when considered together with clinical similarities of chronic graft-vs-host disease and autoimmune disease and the female predilection to autoimmunity, led to the hypothesis that microchimerism is involved in some autoimmune diseases. Sources of engraftment applicable to men and to women who have never been pregnant include from a blood transfusion, a twin sibling, or mother. Initial studies lend support to the hypothesis. A role in disease pathogenesis has not been demonstrated, however, and microchimerism is also common in healthy normals. If microchimerism is involved in the pathogenesis of some autoimmune diseases further understanding potentially may lead to new therapeutic strategies.

Microchimerism in Japanese women patients with systemic sclerosis

To examine whether microchimerism occurs in Japanese women patients with systemic sclerosis, we analysed the Y-chromosome in DNA by PCR. There was no significant difference between patients and healthy people, suggesting that microchimerism may not be the sole pathogenesis in Japanese women with systemic sclerosis.

Microchimerism of maternal origin persists into adult life

Recent studies indicate that fetal cells persist in maternal blood for decades after pregnancy. Maternal cells are known to engraft and persist in infants with immunodeficiency, but whether maternal cells persist long-term in immunocompetent offspring has not specifically been investigated. We developed sensitive human leukocyte antigen-specific (HLA-specific) PCR assays and targeted nonshared maternal HLA genes to test for persistent maternal microchimerism in subjects with scleroderma and in healthy normal subjects. Nonshared maternal-specific DNA was found in 6 of 9 scleroderma patients. In situ hybridization with double labeling for X and Y chromosome-specific sequences revealed female cells in peripheral blood samples from 2 male scleroderma patients. HLA-specific PCR also frequently revealed persistent maternal microchimerism in healthy control subjects. The mean age of all subjects with maternal microchimerism was 28 years (range: 9-49 years). With few exceptions, mothers of subjects with persistent maternal microchimerism were HLA incompatible with subjects for class I and class II alleles. These results clearly indicate that HLA-disparate maternal cells can persist in immunocompetent offspring well into adult life. The biological significance of maternal microchimerism and whether it might contribute to autoimmune disease requires further investigation.

Long-Term Fetal Microchimerism in Peripheral Blood Mononuclear Cell Subsets in Healthy Women and Women With Scleroderma

Fetal CD34+ CD38+ cells have recently been found to persist in maternal peripheral blood for many years after pregnancy. CD34+ CD38+ cells are progenitor cells that can differentiate into mature immune-competent cells. We asked whether long-term fetal microchimerism occurs in T lymphocyte, B lymphocyte, monocyte, and natural-killer cell populations of previously pregnant women. We targeted women with sons and used polymerase chain reaction for a Y-chromosome–specific sequence to test DNA extracted from peripheral blood mononuclear cells (PBMC) and from CD3, CD19, CD14, and CD56/16 sorted subsets. We also asked whether persistent microchimerism might contribute to subsequent autoimmune disease in the mother and included women with the autoimmune disease scleroderma. Scleroderma has a peak incidence in women after childbearing years and has clinical similarities to chronic graft-versus-host disease that occurs after allogeneic hematopoietic stem-cell transplantation, known to involve chimerism. Sixty-eight parous women were studied for male DNA in PBMC and 20 for PBMC subsets. Microchimerism was found in PBMC from 33% (16 of 48) of healthy women and 60% (12 of 20) women with scleroderma, P = .046. Microchimerism was found in some women in CD3, CD19, CD14, and CD56/16 subsets including up to 38 years after pregnancy. Microchimerism in PBMC subsets was not appreciably more frequent in scleroderma patients than in healthy controls. Overall, microchimerism was found in CD3, CD19, and CD14 subsets in approximately one third of women and in CD56/16 in one half of women. HLA typing of mothers and sons indicated that HLA compatibility was not a requirement for persistent microchimerism in PBMC subsets. Fetal microchimerism in the face of HLA disparity implies that specific maternal immunoregulatory pathways exist that permit persistence but prevent effector function of these cells in normal women. Although microchimerism in PBMC was more frequent in women with scleroderma than healthy controls additional studies will be necessary to determine whether microchimerism plays a role in the pathogenesis of this or other autoimmune diseases.

Role of HLA in congenital heart block: susceptibility alleles in children

Congenital heart block (CHB) is a syndrome of uncertain pathogenesis leading to cardiac conduction disturbances in the foetus and newborns. It has been proposed that maternal antibodies transmit immunological injury in the developing foetal heart, thus causing irreversible damage of the atrioventricular node, leading to third-degree atrioventricular block. However, some genetic or environmental factors may also be involved. We have searched for genetic markers that play a role in immune response and that would be pathognomonic for the disease, either in mothers by regulating their immune response or in children by affecting antigen presentation and target for the maternal immune response. We have compared HLA class I and II alleles of the children with their mother and with healthy individuals and searched for HLA markers that would be emphasized in children. We have shown that particular DQ alleles in the child predispose to CHB, perhaps serving as antigen-presenting molecules on site. In addition, the HLA-Cw3 allele is involved, although its function remains to be clarified. In our results, children with CHB were often identical to their mothers in alleles of DRB, DQA and DQB loci, thus affecting foetomaternal recognition and suggesting that cell-mediated mechanisms could be involved in the pathogenesis.

New perspectives on the etiology of systemic sclerosis

Systemic sclerosis (SSc) is a disease of unknown origin. Although SSc is considered to be an autoimmune disease, recent studies have implicated cellular microchimerism in its pathogenesis. Microchimerism results from the persistence of fetal cells, from prior pregnancies, in the maternal circulation. The demonstration of the presence of fetal CD3+ T cells in the maternal circulation and of fetal cells in affected SSc tissues suggests that microchimerism might cause SSc in certain patients by initiating a graft-versus-host-like response.

Rapid clearance of fetal DNA from maternal plasma

Fetal DNA has been detected in maternal plasma during pregnancy. We investigated the clearance of circulating fetal DNA after delivery, using quantitative PCR analysis of the sex-determining region Y gene as a marker for male fetuses. We analyzed plasma samples from 12 women 1-42 d after delivery of male babies and found that circulating fetal DNA was undetectable by day 1 after delivery. To obtain a higher time-resolution picture of fetal DNA clearance, we performed serial sampling of eight women, which indicated that most women (seven) had undetectable levels of circulating fetal DNA by 2 h postpartum. The mean half-life for circulating fetal DNA was 16.3 min (range 4-30 min). Plasma nucleases were found to account for only part of the clearance of plasma fetal DNA. The rapid turnover of circulating DNA suggests that plasma DNA analysis may be less susceptible to false-positive results, which result from carryover from previous pregnancies, than is the detection of fetal cells in maternal blood; also, rapid turnover may be useful for the monitoring of feto-maternal events with rapid dynamics. These results also may have implications for the study of other types of nonhost DNA in plasma, such as circulating tumor-derived and graft-derived DNA in oncology and transplant patients, respectively.

Fetal DNA in skin of polymorphic eruptions of pregnancy

BACKGROUND

Polymorphic eruptions of pregnancy (PEP) are common cutaneous disorders of unknown origin that occur usually after week 34 of gestation. Since pregnancy is associated with peripheral-blood chimerism, particularly during the third trimester, we studied the role of fetal cells in the development of the skin lesions.

METHODS

We studied samples of skin from ten women with PEP who were carrying male fetuses and 26 women with normal skin or non-PEP skin disorders (13 carrying male and 13 carrying female fetuses). Epidermis and dermis were dissected from the samples, and the DNA was extracted. PCR with primers specific for the SRY gene was used to detect male DNA.

FINDINGS

Male DNA was detected in dermis or epidermis from skin lesions of six of the ten women with PEP. No male DNA was detected in any of the 26 women without PEP.

INTERPRETATION

Fetal cells can migrate to skin during gestation, where they seem to be associated with the development of cutaneous disorders of pregnancy.

Pregnancy loss and antiphospholipid antibodies

With the use of low-dose heparin, fetal survival of aPL pregnancies is 70-80%, but prematurity and intrauterine growth restriction are common. It is likely, but not proven, that dysregulated placental coagulation and resultant vasculopathy are the cause of fetal loss. Details of dysregulated coagulation remain to be described. Opportunities remain to determine the role of coagulopathy in repeated pregnancy loss, identify a critical event or window to which intervention might be directed, identify maternal (and fetal) characteristics other than aPL that determine fetal loss, describe toxicity profiles of current treatments, develop more specific, less toxic therapies, and describe long-term fetal and maternal outcomes.